Ch. 3 & 4 Ecology Notes

Ch. 3 & 4Ecology Notes

I. What is Ecology?

A. Ecology – study of interactions between organisms and their environment

Everything is connected

to everything else

I. What is Ecology?

1. Out of ALL of nature’s “houses”, the largest one is the biosphere.

a. Biosphere – all the portions of Earth where life exists (including land, water, and air/atmosphere)

2. The study of ecology ranges from studying an individual organism up until the entire biosphere.

I. What is Ecology?

B. Let’s break it down . . .1. Organism – any individual living thing

a. Species – organisms that breed and produce fertile offspring

I. What is Ecology?

b. Habitat – where an organism livesExample: A zebra lives in the African Savanna.c. Niche – an organism’s role in the environmentExample: Zebras eat grass.

I. What is Ecology?

2. Population – group of same species living in the same area

a. Example: Elephants in the Savanna.

I. What is Ecology?

3. Community – populations of different species living in the same area

a. Example: Elephants, lions, and zebras in the Savanna.

Community

I. What is Ecology?

4. Ecosystem – all the biotic (living) and abiotic (nonliving) parts of an environment

a. Example: Soil, water, air, rock, lions, zebras in the Savanna.

Ecosystem

I. What is Ecology?

5. Biome – group of ecosystems that have the same climate and dominant vegetation

a. Example: Savanna

I. What is Ecology?

b. What major biomes are found throughout the world?

Rainforest

lots of rain, lots of sunlight, always warm

many plants & animals

high biodiversity

Savanna

dry season/wet season, always warm

frequent fires in dry season

many herbivores

mid biodiversity

Desert

very dry, hot in day & cold at night

very few plants & only small animals:reptiles, insects, rodents, birds

low biodiversity

Temperate Grassland (Midwest U.S.)

dry season/wet season, cold winters/hot summers

frequent fires in dry season

many herbivores

mid biodiversity

Temperate Deciduous Forest

4 seasons: warm summer with rains, cold winter with snow

deciduous trees, many mammals, insects, birds, etc.

high biodiversity

Coniferous Forest (Taiga)

northern forest, drier, cooler

evergreens, mammals, birds, insects, etc.

mid biodiversity

Tundra

cold year round, dry, permafrost

only lichens & mosses & mostly migrating animals

low biodiversity

II. How does an ecosystem work?

A. For life to continue within the ecosystem, three things must take place.

1. The sun is the main source of energy for all life on Earth.

2. The cycling of matter and nutrients. 3. Gravity helps to hold everything in place, including

the atmosphere and helps to move nutrients through their cycles.

II. How does an ecosystem work?

B. All things in an ecosystem can be classified as biotic or abiotic.

1. Biotic – anything living (or once living)Example:2. Abiotic – anything nonliving (never alive)Example:

II. How does an ecosystem work?

C. Classification of Organisms1. Producers/Autotrophs – organisms who

make their own food, usually through photosynthesis

a. Example: Plants, algae, some bacteria

II. How does an ecosystem work?

b. Chemosynthesis – method used by bacteria to create food in the absence of

light using hydrogen sulfide gasExample: Bacteria that live in deep sea vents.

II. How does an ecosystem work?

2. Consumers/Heterotrophs – organisms who cannot make their own food, and must consume food to survive

a. Herbivores - feed on plants/producers

- Also called primary consumers.- Example:

II. How does an ecosystem work?

b. Carnivores – feed on other animals/consumers

- Secondary Consumers – feed nly on primary consumers

- Example: - Tertiary Consumers – feed

only on secondary consumers - Example:

II. How does an ecosystem work?c. Omnivores – feed on both producers and consumers- Example: Raccoons, bears, rats

II. How does an ecosystem work?d. Detrivore Consumers – feed only on detritus- Detritus – parts of dead organisms, wastes

of organisms

- Example: Earthworms, crabs, ants

II. How does an ecosystem work?e. Decomposers – break down organic

matter so that it can be recycled

- Example: Bacteria, Fungi

III. How does energy move through ecosystems??

A. Remember, energy can only flow in one direction.1. Energy flows from sun producers consumers.

III. How does energy move through ecosystems??

2. Methods to examine energy flow through an ecosystem:

a. Food Chain – a series of steps where organisms transfer energy by eating and being eaten; shows one feeding relationship

- Example:

III. How does energy move through ecosystems??

b. Food Web – multiple linked food chains demonstrating the complex interactions in a community; shows many feeding relationships- Example:

III. How does energy move through ecosystems??

III. How does energy move through ecosystems??

c. Each step in a food chain or food web is called a trophic level.- Producers – 1st trophic level- Consumers – 2nd, 3rd, 4th trophic levels

III. How does energy move through ecosystems??

d. Trophic levels- Each consumer depends upon the trophic level below it for energy!

- Only 10 % of the energy is transferred from level to level.- The other 90% is used by the organism for metabolism, respiration, movement, reproduction, growth, and given off as body heat.

III. How does energy move through ecosystems??

sun

secondary consumers(carnivores)

primary consumers(herbivores)

producers (plants)

loss of energy

loss of energy

loss of energy

III. How does energy move through ecosystems??

e. Ecological Pyramids – illustrate the relative amounts of energy or matter contained within each trophic level

1,000,000,000

100,000

100

1

Numbers

III. How does energy move through ecosystems??

- Energy Pyramid – illustrates the amount of energy usually in kCals or Joules (J), available

III. How does energy move through ecosystems??

- Biomass Pyramid – illustrates the total amount of living tissue in a trophic level, usually in g/unit area

III. How does energy move through ecosystems??

- Numbers Pyramid – illustrates the actual number of individual organisms in each trophic level

III. How does energy move through ecosystems??

IV. Community Interactions

IV. Community Interactions A. Symbiosis – relationship in which two species live closely together

1. Mutualism – a relationship where both species benefita. Example: Flowers depend on bees to pollinate them.

- Flowers Reproduce- Bees Get food

b. Example: Birds on back of buffalo.- Birds Food- Buffalo Get cleaned/protections from parasites

IV. Community Interactions

2. Commensalism – a relationship where one species benefits and the other is unaffected

a. Example: Barnacles attaching to a whale.- Barnacle Filters water to get food- Whale Unaffected

b. Example: Orchids growing up trees in Rainforest.

- Orchids More sunlight- Tree Unaffected

IV. Community Interactions

3. Parasitism – a relationship where one species benefits and the other is harmed

a. Example: Tick (parasite) on a deer (host).b. Example: Tapeworms (parasite) in animal intestines (host).

IV. Community Interactions

B. Other interactions1. Competition – Organisms attempt to use a

resource at the same time in the same place

IV. Community Interactions

2. Predation – one organism (predator) captures and kills another organism (prey)

a. Example: Lion hunts and kills wildebeest.

V. How is matter cycled?

A. Remember, there is only one way energy can flow through an ecosystem, but matter must be recycled throughout the ecosystem.

1. Energy is moved through parts of an ecosystem through biogeochemical cycles.

a. Example: Water, Sulfur, Phosphorous, Carbon, Nitrogen Cycles

nutrients

decomposers

V. How is matter cycled?

B. Nutrients – molecules that an organism needs to sustain life

1. Used to build tissues and carry out metabolism.

a. Example: CHONPS

nutrients

decomposers

V. How is matter cycled?

C. Important Cycles1. Hydrologic Cycle

a. Importance: Every living thing requires water.

V. How is matter cycled?

b. Key Processes:- Evaporation – liquid gas- Transpiration – evaporation from plant leaves- Condensation – gas liquid

V. How is matter cycled?

- Precipitation – rain, sleet, snow, hail- Runoff – water moving downhill into streams/rivers- Infiltration – water soaking into the soil

Evaporation

Condensation

Precipitation Transpiration

Runoff

V. How is matter cycled?

2. Carbon Cycle a. Importance:

- Carbon is used in making living tissues and animal skeletons.

V. How is matter cycled?

- Carbon regulates temperature in the atmosphere (carbon dioxide).- Plants Photosynthesis pass along glucose in food webs.

V. How is matter cycled?

b. Key Processes:- Photosynthesis – how autotrophs produce glucose (food) while removing carbon dioxide from the air - CO2 + H2O + Light C6H12O6 + O2

- Cellular Respiration – how all organisms break down food to get ATP energy and release carbon dioxide in the air - C6H12O6 + O2 CO2 + H2O + ATP

V. How is matter cycled?

- Decomposition – bacteria and fungi break down dead organisms and release their nutrients in the soil and carbon dioxide in the air

- Creates fossil fuels with extreme pressure

- Combustion – burning of fossil fuels (coal, oil, natural gas) and trees releases carbon dioxide into the air; this can lead to global warming

CO2

Burning FF

CR by plants/animals

DecompositionFossil Fuel formation

PSBurning plants

V. How is matter cycled?

3. Nitrogen Cyclea. 78% of the atmosphere is nitrogen. However, this is mostly not usable by animals and plants.

V. How is matter cycled?

b. Importance:- Plants and animals could not live without nitrogen.- Nitrogen makes up the cell parts of living things, as well as amino acids, proteins, and DNA.- Nitrogen is needed to make chlorophyll in plants, which is needed for plants to go through photosynthesis.

V. How is matter cycled?

c. Key Processes:- Fixation – Bacteria changes nitrogen into ammonia.

V. How is matter cycled?

- Nitrification – Ammonia changes into nitrates by bacteria. Nitrates are what plants can absorb.

V. How is matter cycled?

- Assimilation – Plants absorb nitrates from soil. Nitrogen gets used in amino acids, nucleic acids, and chlorophyll.

V. How is matter cycled?

- Ammonification – When a plant/animal dies, decomposers break nitrogen down into ammonia, so nitrogen can re-enter the cycle.

V. How is matter cycled?

- Denitrification – Bacteria transfer any extra nitrogen in the soil back out into the air.